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Fri, 17 Jul 2020 05:47:29 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id B2C34C433C6; Fri, 17 Jul 2020 05:47:28 +0000 (UTC) Received: from tingweiz-gv.qualcomm.com (unknown [180.166.53.21]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: tingwei) by smtp.codeaurora.org (Postfix) with ESMTPSA id 4448CC433C9; Fri, 17 Jul 2020 05:47:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 4448CC433C9 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=tingwei@codeaurora.org From: Tingwei Zhang To: Mathieu Poirier , Suzuki K Poulose , Alexander Shishkin Subject: [PATCH v3 19/20] coresight: add try_get_module() in coresight_grab_device() Date: Fri, 17 Jul 2020 13:45:35 +0800 Message-Id: <20200717054536.7052-20-tingwei@codeaurora.org> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20200717054536.7052-1-tingwei@codeaurora.org> References: <20200717054536.7052-1-tingwei@codeaurora.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200717_014750_943406_D71CBA24 X-CRM114-Status: GOOD ( 15.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tsoni@codeaurora.org, Sai Prakash Ranjan , Kim Phillips , Mao Jinlong , Greg Kroah-Hartman , coresight@lists.linaro.org, Randy Dunlap , Mian Yousaf Kaukab , Russell King , Tingwei Zhang , Leo Yan , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When coresight device is in an active session, driver module of that device should not be removed. Use try_get_module() in coresight_grab_device() to prevent module to be unloaded. Signed-off-by: Tingwei Zhang --- drivers/hwtracing/coresight/coresight.c | 27 +++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 55b699aca9ec..eabb59531c75 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -655,7 +655,7 @@ struct coresight_device *coresight_get_sink_by_id(u32 id) * don't appear on the trace path, they should be handled along with the * the master device. */ -static void coresight_grab_device(struct coresight_device *csdev) +static int coresight_grab_device(struct coresight_device *csdev) { int i; @@ -663,10 +663,25 @@ static void coresight_grab_device(struct coresight_device *csdev) struct coresight_device *child; child = csdev->pdata->conns[i].child_dev; - if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) { + if (!try_module_get(child->dev.parent->driver->owner)) + goto err; pm_runtime_get_sync(child->dev.parent); + } } + if (!try_module_get(csdev->dev.parent->driver->owner)) + goto err; pm_runtime_get_sync(csdev->dev.parent); + return 0; +err: + for (i--; i >= 0; i--) { + struct coresight_device *child; + + child = csdev->pdata->conns[i].child_dev; + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) + pm_runtime_put(child->dev.parent); + } + return -ENODEV; } /* @@ -678,12 +693,15 @@ static void coresight_drop_device(struct coresight_device *csdev) int i; pm_runtime_put(csdev->dev.parent); + module_put(csdev->dev.parent->driver->owner); for (i = 0; i < csdev->pdata->nr_outport; i++) { struct coresight_device *child; child = csdev->pdata->conns[i].child_dev; - if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) { pm_runtime_put(child->dev.parent); + module_put(child->dev.parent->driver->owner); + } } } @@ -736,7 +754,8 @@ static int _coresight_build_path(struct coresight_device *csdev, if (!node) return -ENOMEM; - coresight_grab_device(csdev); + if (coresight_grab_device(csdev)) + return -ENODEV; node->csdev = csdev; list_add(&node->link, path); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel